RESUMO
Many individual monitoring services (IMSs) have long experience in delivering high-quality dosimetry, and many follow rigorous quality assurance (QA) procedures. Typically, these procedures have been developed through experience and are highly effective in maintaining high-quality dose measurements. However, it is not always clear how the range of QA procedures normally followed by IMSs maps on to the various requirements of ISO 17025. The Personal Dosimetry Service of Public Health England has interpreted its QA procedures both in operating existing services and in developing a new one.
Assuntos
Radiometria/métodos , Dosimetria Termoluminescente/métodos , Calibragem , Inglaterra , Humanos , Garantia da Qualidade dos Cuidados de Saúde/normas , Controle de Qualidade , Doses de Radiação , Dosímetros de Radiação , Proteção Radiológica/métodos , Radiometria/instrumentação , Radiometria/normas , Dosagem Radioterapêutica , Dosimetria Termoluminescente/instrumentação , Dosimetria Termoluminescente/normas , IncertezaRESUMO
In support of research aimed at developing a thermoluminescence dosemeter capable of accurately measuring ionising radiation doses to the lens of the eye, Monte Carlo modelling of a standard beta exposure set-up has been performed. It was found that electrons with an energy distribution corresponding to the beta emission spectrum from (85)Kr deposit negligible doses at a depth of 3 mm in tissue, but doses from (90)Sr/(90)Y are significant; free in air and fluence-to-Hp(3,θ°) and -Hp(0.07,θ°) conversion coefficient data were found for this field for exposures at 0°, 30° and 60° angles of incidence, and the response characteristics of the new eye dosemeter were evaluated. It was shown that the results were not affected greatly by the shape of the calibration phantom. However, it was demonstrated that the presence of intermediating air and beam flattening filters hardens the energy distribution of the field at the point of test, relative to a raw (90)Sr/(90)Y source, and this impacts dose depositions.
Assuntos
Olho/efeitos da radiação , Radioisótopos de Criptônio/análise , Modelos Estatísticos , Método de Monte Carlo , Eficiência Biológica Relativa , Radioisótopos de Estrôncio/análise , Radioisótopos de Ítrio/análise , Simulação por Computador , Elétrons , Humanos , Imagens de Fantasmas , Fótons , Doses de Radiação , Proteção RadiológicaRESUMO
A new head band dosemeter, for the measurement of eye lens dose in terms of Hp(3), has been type tested by Public Health England's Centre for Radiation, Environmental and Chemical Hazards [formerly part of the UK Health Protection Agency (HPA)]. The type tests were based on the International Standard ISO 12794, drawing also upon earlier work at HPA. The results show that, unlike many existing dosemeters, the new head band dosemeter correctly measures Hp(3) for beta radiations as well as photons.
